Projection optical system, a projection exposure apparatus provided with the same, as well as a device manufacturing method

ABSTRACT

The present invention is directed toward a high performance yet compact projection optical system that is both-sidedly telecentric, has the ability to minimize the reduction of image formation performance that occurs due to the absorption by the glass material used, can secure a sufficiently large numerical aperture and a broad exposure area, and has the ability to very favorably correct aberrations and especially distortion. In a projection optical system that projects a pattern of a first object onto a second object, comprising in order from the first object side, a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, and positive fifth lens group that provides at least 2 negative lens compositions, and where the fifth lens group includes two lens planes that satisfy the expression φ/φexp≦3.5, and a first lens composition L 59  constituted of a first material that satisfies the expression n≦1.57, and where the entire projection optical system described above has two lens planes that satisfy the expression φ/φexp&gt;3.5, and which includes a second lens composition L 34  constituted of a second material that satisfies the expression n&gt;1.57.

This is a continuation of application Ser. No. 09/587,269, filed Jun. 5,2000, now U.S. Pat. No. 6,600,550.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a manufacturing method of a device(such as a semiconductor elemental device, photo-imaging elementaldevice, flat panel display device such as a LCD (liquid crystal display)element device, a PDP (plasma display panel) element device, EL(electroluminescent) display element device, FED (field emissiondisplay) element device, Electric Paper display element device etc.,thin film magnetic head elemental device, and so forth) that uses aprojection exposure apparatus at the time of photo-transferring a maskpattern onto a substrate within the process of lithography formanufacturing the device, wherein the projection optical system forprojecting the image of the pattern of the first object onto the secondobject and the projection optical system thereof are provided.

2. Description of the Related Art

When manufacturing a semiconductor elemental device or so forth, aprojection exposure apparatus in a scanning exposure format is used likethat of a batch exposure format or the step-and-scan method where astepper is used to transfer an image of a reticle pattern through aprojection optical system as a mask onto a wafer (or glass plate or soforth) that has a photo resist applied thereon. Further, in accordancewith the advancement of the refining of patterns such as that of asemiconductor integrated circuit, the demand for increased performancein the projection optical system used in these projection exposureapparatuses is growing, especially in regards to the improvement of theresolving power of a projection optical system. In order to improve thisresolving power, the shortening of the exposure wavelength or theincreasing of the numerical aperture (N.A.) can be conceived.

With the projection exposure apparatus described above, the i line (365nm) from the g line (436 nm) of the mercury vapor lamp is used as theexposure light with recent trends moving towards a shorter wavelength.For this reason, a projection optical system that can be used inconjunction with a short wavelength exposure light is being developed.

Furthermore, in conjunction with the improvement of the resolving power,the demand for minimized image warping in projection optical systems isever increasing. In addition to that caused by distortion, whichoriginates in the projection optical system, there is image warping thatis caused by the bend of the wafer that is printed by the image side ofthe projection optical system as well as that caused by the bend of thereticle drawn by the circuit pattern on the object side of theprojection optical system.

In recent years, the refinement of the transferred pattern isincreasingly advanced, and the demand for minimized image warping isever increasing. Therefore, in order to reduce the effect on the imagewarping due to the bend of the wafer, a so-called image-side telecentricoptical system has been conventionally used that places the image sideexit pupil position of the projection optical system farther away.

Meanwhile, in regard to the reduction of the image warping due to thebend of the reticle, a so-called object-side telecentric optical systemcan be conceived that places the entrance pupil position of theprojection optical system farther away from the object plane, and thereare proposals for moving the entrance pupil position of the projectionoptical system comparatively farther away in this manner.

In order to improve the resolving power, the problem lies in thereduction of the transmission factor of the glass material constitutesthe projection optical system when using an exposure light with a shortwavelength, and in the limited availability of glass material that canbe used to secure a high transmission factor. Furthermore, the reductionof the transmission factor is not due exclusively to the loss of theamount of light. Rather, because a portion of the lost light is absorbedinto the glass material and through its conversion to heat energy, therefractive index of the glass material of the lens changes or the shapeof the lens surface changes, thereby resulting in a reduction of theperformance of image formation and especially causing fluctuation in theaberration in the exposure. Moreover, the aberration fluctuation in theexposure is also a reverse phenomenon since it disappears when the heatenergy in the lens composition disappears after completing exposure, orin other words, when the heated lens cools.

SUMMARY OF THE INVENTION

The advantages and purposes of the invention will be set forth in partin the description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. Moreover,the advantages and purposes of the invention will be realized andattained by means of the elements and combinations particularly pointedout in the appended claims.

The present invention takes into account the exemplary problemsdescribed above in providing a compact yet high performance projectionoptical system that is extremely favorable in correcting distortion,various aberrations, and maintaining a sufficiently large numericalaperture as well as a broad exposure area while minimizing the reductionin image formation performance due to the absorption by the glassmaterial used, and it is telecentric relative to both sides.

To solve the exemplary problems described above, the present inventionprovides, in a projection optical system for projecting the pattern of afirst object onto a second object, in order from the first object side,a first lens group having a positive refractive power, a second lensgroup having a negative refractive power, a third lens group having apositive refractive power, a fourth lens group having a negativerefractive power, and a fifth lens group having a positive refractivepower and which provides at least two negative lenses.

The first lens group, while maintaining telecentricity, mainlycontributes to the correction of the distortion. The second lens groupand the fourth lens group contribute mainly to the correction of thePetzval sum and achieve desired flattening of the image plane. Further,the third lens group, in conjunction with the first lens group,generates positive distortion thereby performing the function ofcorrecting the negative distortion generated by the second, fourth andfifth lens groups. In addition, the third lens group and the second lensgroup, when viewed from the second object, are composed of a telephotosystem having a positive and negative refractive power arrangement, andon account of this, have a function that prevents the elongation of theentire projection optical system. The fifth lens group, in order tosufficiently respond to the high numerical aperture at the second objectside, suppresses the generation of distortion by maintaining a state ofextreme avoidance of especially spherical aberration and therebyperforms the role of image formation by leading the luminous flux to thesecond object.

Further, it is favorable when the present invention satisfies thefollowing conditional expressions (1), (2), (3), and (4). The fifth lensgroup includes a first lens, two lens surfaces of the first lens satisfythe following condition (1):φ1/φexp≦3.5  (1)

the first lens made of a first material having a refractive index thatsatisfies the following condition (2):n1≦1.57  (2)where φexp is a diameter of an exposure area on the second object; φ1 isa diameter of a clear aperture of the two lens surfaces of the firstlens; and n1 is a refractive index of the first lens. Further, theradius of the clear aperture indicates the distance from the opticalaxis to the point where reach the reverse traced marginal ray of thebeam has the maximum numerical aperture, from the peripheral point ofthe maximum exposure area where practically corrected aberrations (clearaperture diameter of a lens surface indicates a diameter of a circleincluding an area of section of a whole beam which pass through the lenssurface). Moreover, the exposure area indicates the area defined by thecircle where the length of the diagonal line of the short exposure area,or in other words, the area defined by that short exposure areainscribed by or included within the circle. The exposure area diameterindicates the diameter of the circular exposure area described above.

Preferably, the glass (i.e., optical glass) material has a bettertransmission factor in the short wavelength area than general glassmaterial having a low refractive index. Moreover, the position of thelens that satisfies conditional expression (1) can be regarded as a highenergy density of exposure light position. Since a lens having exposurelight with a high energy density secures a higher transmission factor, aglass material having a refractive index that satisfies the conditionalexpression (2) is used. Accordingly, the reduction of the imageformation performance that occurs on account of the reduction of thetransmission factor can be suppressed.

On the other hand, the use of a glass material having a refractive indexthat exceeds the upper limit value of conditional expression (2) as thelens having exposure light with a high energy density which satisfiesconditional expression (1), is not favorable because it leads to thereduction of the image formation performance, which occurs due to thereduction in the transmission factor.

Furthermore, with the present invention, the entire projection opticalsystem preferably includes a second lens with two lens surfaces thatsatisfy the following condition (3):

 φ2/φexp>3.5  (3)

where φ2 is a diameter of a clear aperture of the two lens surfaces ofthe second lens, the second lens made of a second material has arefractive index (n2) that satisfies the following condition (4):n>1.57   (4)By providing a composition that has 1 or more lenses of a lens thatsatisfy conditional expression (4) in a lens that is comparatively lowin energy density of the exposure light that satisfies conditionalexpression (3), the refractive power in the entire projection opticalsystem is improved. In this way, favorable aberration correction ispossible and a compact optical system can be obtained. Conversely, byproviding a lens that does not completely satisfy conditional expression(4) but is comparatively low in energy density of the exposure lightthat satisfies conditional expression (3), the refractive power in theentire projection optical system is unable to be increased, which leadsto unfavorable elongation of the projection optical system.

In addition, the present invention preferably satisfies the followingconditional expressiont 5′/t 5≧0.2  (5)where the parameter t5 is defined as the sum of the thickness along theoptical axis of all of the lenses constituting the fifth lens groupdescribed above, and the parameter t5′ is defined as the sum of thethickness along the optical axis of a first lens in the fifth lens groupdescribed above.

Conditional expression (5) regulates the ratio of the sums of thicknessof the glass material used to raise the transmission factor since theenergy density of exposure light is comparatively high in relation tothe sum of the thickness of the glass material in the fifth lens groupthat performs the function of image formation and which leads the beamonto the second object. By satisfying the conditional expression (5), itbecomes possible to suppress the reduction of the image formationperformance that occurs due to the reduction of the transmission factor.Exceeding the upper limit value of conditional expression (5) leads to areduction of the image formation performance that occurs due to thereduction of the transmission factor.

Moreover, with the present invention, f1 designates the focal length ofthe first lens group; and f2 designates the focal length of the secondlens group; and f3 designates the focal length of the third lens group;and f4 designates the focal length of the fourth lens group; and f5designates the focal length of the fifth lens group; and L designatesthe axial distance from the first object to the second object.Preferably, the present invention satisfies at least one of thefollowing (6) through (10) conditions.0.04<f 1 /L<0.4  (6)0.015<−f 2/L<0.15  (7)0.02<f 3/L<0.2  (8)0.015<f 4/L<0.15  (9)0.03<f 5/L<0.3  (10)More preferably, the present invention operates most effectively wheneach of the conditions (6) through (10) described above aresimultaneously satisfied.

Conditional expression (6) regulates the range of optimal refractivepower for the first lens group. When exceeding the upper limit value ofconditional expression (6), the positive distortion generated by thefirst lens group becomes less able to correct the negative distortiongenerated by the second, fourth and fifth lens groups and is thereforeunfavorable. When falling below the lower limit value of the conditionalexpression (6), this becomes the cause of the generated higher orderpositive distortion and is therefore not favorable.

Conditional expression (7) regulates the range of optimal refractivepower for the second lens group. When exceeding the upper limit value ofconditional expression (7), the correction of the Petzval sum becomesinsufficient and it becomes more difficult to achieve the flattening ofthe image plane. Therefore, exceeding such an upper limit isunfavorable. Conversely, when falling below the lower limit ofconditional expression (7), the generation of negative distortionbecomes larger, thereby making it more difficult to favorably correctthis larger negative distortion with only the first and third lensgroups. As a result, falling below this lower limit is also notfavorable.

Conditional expression (8) regulates the range of optimal refractivepower for the third lens group. When exceeding the upper limit value ofconditional expression (8), the telephoto ratio of the telephoto systemformed by the combination of the second lens group and the third lensgroup becomes larger, and in addition to leading to the elongation ofthe entire projection optical system, the generated amount of positivedistortion generated by the third lens group becomes smaller therebybecoming less effective in favorably correcting the negative distortiongenerated by the second, fourth and fifth lens groups, and therefore isnot favorable. Conversely, when falling below the lower limit value ofthe conditional expression (8), high order spherical aberration isgenerated thereby making it not possible to obtain favorable imageformation performance on the second object and therefore is notfavorable.

Conditional expression (9) regulates the range of optimal refractivepower for the fourth lens group. When exceeding the upper limit value ofconditional expression (9), the correction of the Petzval sum becomesinsufficient and it becomes more difficult to achieve the flattening ofthe image plane and therefor it is unfavorable. Conversely, fallingbelow the lower limit of conditional expression (9) causes thegeneration of a high order spherical aberration and a comatic aberrationand therefore is not favorable.

Moreover, conditional expression (10) regulates the range of optimalrefractive power for the fifth lens group. When exceeding the upperlimit value of conditional expression (10), the refractive power of theentire fifth lens group becomes too weak, thereby leading to theelongation of the entire projection optical system and therefore is notfavorable. Conversely, falling below the lower limit value ofconditional expression (10) generated a high order spherical aberrationthereby leading to a reduction in the image contrast on the secondobject and therefore is not favorable.

Furthermore, the present invention preferably employs at least onenegative lens in the fifth lens group that satisfies the followingconditional expressionφ5n/φ5max≧0.7,  (11)where φ5n designates the maximum clear aperture diameter among clearapertures of negative lenses in the fifth lens group, and φ5max isdesignated as the maximum clear aperture diameter among the clearapertures of a plurality of lenses in the fifth lens group.

By the clear aperture diameter of at least one negative lens included inthe fifth lens group satisfying the conditional expression (11), thenegative spherical aberration generated by the fifth lens group iseffectively corrected thereby making it possible for a high contrastimage to be formed on the second object. On the other hand, if the clearaperture of at least one negative lens included in the fifth lens groupwere to fall below the lower limit of the conditional expression (11),the negative spherical aberration generated by the fifth lens groupcould not be corrected, thereby leading to a reduction in the contrastof the image on the second object and therefore it is not favorable.

Furthermore, the present invention preferably operates when thefollowing conditional expression.F/L≧0.6,  (12)is satisfied. Here, F represents the focal length of the projectionoptical system, and L refers to the distance from the first object tothe second object. Conditional expression (12) regulates the conditionfor establishing both-sided telecentricity (bi-telecentricity). Bysatisfying conditional expression (12), it becomes possible to achievean optical system that does not generate image distortion even if thereis bending in the reticle and wafer.

Further, the present invention provides a projection exposure apparatuscomprising a first stage for holding the mask for the first object, andan illumination optical system for illuminating the mask, and a secondstage for holding the substrate for the second object, and a projectionoptical system for projecting and exposing the image of the pattern ofthe illuminated mask onto the substrate from the illumination opticalsystem.

Since the projection optical system according to the present inventionprovides both-sided telecentricity and a large numerical aperture, inconjunction with being capable of obtaining a high resolution, theprojection magnification does not change even if there is curving in themask or substrate. Furthermore, since a broad exposure area can beobtained, a large pattern can be exposed at once. Moreover, by the useof a glass material having a high transmission factor with a lowrefractive index, the reduction to the image formation performanceoccurring due to the absorption by the glass material can be suppressed,thereby achieving a high image formation performance.

Additionally, the present invention provides a device manufacturingmethod comprised so as to have a process for applying photo-sensitivematerial onto a substrate as the second object, and a process forprojecting the image of the pattern of the mask of the first objectthrough the projection optical system described in Claims 1 or 2 ontothe substrate, and a process for developing the photo-sensitive materialonto the substrate, and a process for forming a predetermined circuitpattern onto the substrate as a mask of the photo-sensitive materialsubsequent to developing. By the use of the projection exposureapparatus of the present invention, a circuit pattern for use with adevice can be formed with a high resolution onto a substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention. In the drawings,

FIG. 1 illustrates the schematic view of the projection exposureapparatus that provides the projection optical system related to anembodiment of the present invention;

FIG. 2 illustrates the lens sectional view of the projection opticalsystem that relates to a first embodiment of the present invention;

FIG. 3 illustrates the longitudinal aberration of the projection opticalsystem that relates to the first embodiment of the present invention;

FIG. 4 illustrates the lateral aberration of the projection opticalsystem that relates to the first embodiment of the present invention;

FIG. 5 illustrates the lens sectional view of the projection opticalsystem that relates to the second embodiment of the present invention;

FIG. 6 illustrates the longitudinal aberration of the projection opticalsystem that relates to the second embodiment of the present invention;

FIG. 7 illustrates the lateral aberration of the projection opticalsystem that relates to the second embodiment of the present invention;

FIG. 8 illustrates the lens sectional view of the projection opticalsystem that relates to the third embodiment of the present invention;

FIG. 9 illustrates the longitudinal aberration of the projection opticalsystem that relates to the third embodiment of the present invention;

FIG. 10 is a drawing that shows the lateral aberration of the projectionoptical system that relates to the third embodiment of the presentinvention;

FIG. 11 is a flow diagram illustrating the semiconductor devicemanufacturing method that employs the projection optical system involvedwith the embodiments of the present invention;

FIG. 12 illustrates the exposure system of the present invention;

FIG. 13A illustrates the relation between the exposure area, the imagefield, and the exposure area;

FIG. 13B illustrates the relation between the image field and theexposure field;

FIG. 14 is a schematic view of the projection exposure apparatus shownin FIG. 12; and

FIG. 15 is a flow diagram illustrating an exemplary exposure process ofthe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the invention illustrated in the accompanying drawings.Wherever possible, the same reference numbers are used throughout thedrawings to refer to the same or like parts.

Hereafter, an example of the embodiment of the present invention will bedescribed with reference to figures. FIG. 1 is a drawing briefly showingthe entire configuration of the projection exposure apparatus thatprovides the projection optical system related to each embodiment of thepresent invention. Moreover, FIG. 1 establishes axis Z that is parallelto the optical axis AX of the projection optical system PL, and itestablishes the X axis that is parallel to the surface of the paper forFIG. 1 in an orthogonal plane to optical axis AX, and it establishesaxis Y being orthogonal to the surface of the paper. Further, thereticle R is arranged as a projection original being formed by apredetermined circuit pattern on the object plane of the projectionoptical system PL, and the wafer W that is applied by the photoresist asa substrate is arranged on the image plane of projection optical systemPL.

The light that is emitted from the light source L, through theillumination system IS, illuminates uniformly the reticle R that isformed by the predetermined pattern. Furthermore, one or more foldingmirrors (not shown) are arranged to change the light path as necessaryfrom the light source L to the light path of the illumination system IS.

Furthermore, the illumination system IS, for example, has a variablefield stop (reticle blind), an optical system such as a field stop(reticle blind) imaging optical system that projects an image of thefield stop onto a reticle, for regulating the size and shape of theillumination area on the reticle R and the optical integrator that formsthe secondary light source of a predetermined size and shape from aninternal reflecting integrator and a fly's eye lens for unifying theilluminated portion of the exposure light. Moreover, the illuminationsystem disclosed in U.S. Pat. No. 5,345,292 for example, can be given asan applicable optical system from the light source L to the field stop.

The reticle R, through the reticle holder RH, is kept parallel to theflat plane XY on the reticle stage RS. In the reticle R, the pattern tobe transferred is formed, and the entire pattern area is illuminatedwith light from the illumination system IS. The reticle stage RS isarranged so as to, by way of the action of the drive system that isomitted from the figure, have the ability to move two dimensionallyalong the reticle plane (in other words, the XY plane), and the positioncoordinates thereof are measured and such position controlled by theinterferometer IF1 that uses the reticle movement mirror M1.

The light from the pattern that is formed by the reticle R_(i) throughthe projection optical system PL, forms the mask pattern image on thewafer W that is a photosensitive plate (workpiece). The projectionoptical system PL, in addition to having an aperture stop (AS) with avariable opening diameter in the vicinity of the pupil position thereof,is essentially telecentric with respect to the reticle R side and thewafer W side.

The wafer W, through the wafer holder WH, is held parallel to the flatplane XY on the wafer stage WS. Further, the pattern image is formed inthe exposure area of essentially the same shape as the illumination areaon the reticle R.

The wafer stage WS is arranged so as to, by way of the action of thedrive system that is omitted from the figure, have the ability to movetwo dimensionally along the wafer plane (in other words, the XY plane),and the position coordinates thereof are measured and such positioncontrolled by the interferometer IF2 that uses the wafer movement mirrorM2.

After performing the position alignment of the reticle R and the wafer Wusing the interferometers (IF1, IF2) and the drive system describedabove and the alignment system not shown in the figure, and afterdetermining the position of the wafer W to the image formation plane ofthe projection optical system by using the autofocus and autolevelingsystem not shown in the figure, the pattern of the reticle R istransferred to one exposure area (short area) on the wafer 1 byilluminating the exposure light onto the pattern area of the reticle R.Thereafter, the wafer is moved within the XY plane using the drivesystem and interferometer (IF) then the pattern of reticle R istransferred to an area on wafer W that is different from the exposurearea described above.

I. PREFERRED EMBODIMENT EXAMPLE 1

FIG. 2 is a drawing that shows the lens construction of the projectionoptical system that relates to the first embodiment. This embodimenthas, relative to the reticle R (object plane) as the first object, afirst lens group G1 having a positive refractive power and with at leastone negative lens L11; and a second lens group G2 having a negativerefractive power; and a third lens group G3 having a positive refractivepower; and a fourth lens group G4 having a negative refractive power;and a fifth lens group G5 having a positive refractive power with atleast two negative lenses L54 and L58. Furthermore, it is both-sidedlytelecentric on the wafer W (image plane) side for the second object andthe reticle R (object plane) side.

Further, with the fifth lens group described above of the projectionoptical system of FIG. 2, the lens L59, L510, L511 are comprised so asto satisfy the conditional expressions (1) and (2). In this manner, ahigher transmission factor can be secured in a lens with a high energydensity of the exposure light thereby making it possible to suppress thereduction of the image formation performance that occurs due to thereduction of the transmission factor.

In addition, the present invention employs one or more lenses with lenscomposition L34 that satisfies conditional expressions (3) and (4). Inthis manner, a higher refractive index can be secured in a lens withcomparatively low energy density for the exposure light thereby makingfavorable aberration correction possible and realizing a compact opticalsystem.

In the fifth lens group G5, the lens L59, L510, L511 that satisfy theconditional expressions (1) and (2) satisfy the conditional expression(5). In this manner, a higher transmission factor can be secured in alens with a high energy density of the exposure light thereby making itpossible to suppress the reduction of the image formation performancethat occurs due to the reduction of the transmission factor.

Moreover, the focal length between each of the lens groups G1 through G5satisfies the conditional expressions (6) through (10). Accordingly,while being both-sidedly telecentric and securing a sufficiently highnumerical aperture and broad exposure area, it realizes a highperformance yet compact projection optical system, which has the abilityto very favorably correct various aberrations and especially distortion.Furthermore, this embodiment preferably performs best when allconditional expressions (6) through (10) are simultaneously satisfied.

In addition, at least one negative lens L54 of the fifth lens group G5satisfies conditional expression (11). In this manner, the negativespherical aberration generated by the fifth lens group G5 is effectivelycorrected thereby making it possible to realize a high contrast imageformation on the second object W.

The various values of the projection optical system that relate to thefirst embodiment are given in Table 1. In Table 1, DO is the distance onthe optical axis from the reticle R (first object) to the lens plane ofthe extreme reticle R of the first lens group G1; and WD is the distance(working distance) on the optical axis from the lens plane of theextreme wafer W (second object) side of the fifth lens group G5; and theb is the projection magnification (lateral magnification) of theprojection optical system; and the N.A. is the numerical aperture of thewafer W side of the projection optical system; and the φexp is thediameter of the exposure area (projection area) of the circle in thewafer W plane of the projection optical system; and the L is thedistance on the optical axis between the images (i.e., between thereticle R and the wafer W). Further, in the lens data, the Numberindicates order of the lens plane from the reticle R (first object); andthe r indicates the curvature radius of said lens plane; and the dindicates the spacing on the optical axis from said lens plane to thenext lens plane; and the n indicates the glass material refractive indexwith respect to the i line (λ=365.015 nm); the φ indicates the clearaperture diameter of said lens plane. Moreover, the same reference codesare used to indicate the various values for all of the embodied examplesto follow as in the present embodied example. The unit of measure forall examples used indicating the curvature radius r, the spacing on theoptical axis d, and the clear aperture diameter φ that occur in thevarious values of each of the following embodied examples, can beexpressed in mm.

Lens Data for Example 1

Parameters:

-   -   DO=109.413    -   WD=26.848    -   β=−0.250    -   N.A.=0.520    -   φexp=42.000    -   L=1250.000    -   F=939.165

TABLE 1 Lens data Number R d n φ 1 791.172 22.500 1.61265 198.4 L11 2273.340 2.002 1.00000 200.7 3 281.205 39.197 1.46393 201.8 L12 4−573.625 1.000 1.00000 203.6 5 408.697 29.644 1.46393 205.2 L13 6−1006.144 1.000 1.00000 203.9 7 256.563 31.008 1.61548 197.0 L14 8353422.707 1.000 1.00000 191.6 9 229.781 22.000 1.61548 176.5 L21 10126.728 20.093 1.00000 152.2 11 427.536 16.970 1.61548 151.6 L22 122267.800 1.000 1.00000 146.8 13 1593.511 15.000 1.46393 145.9 L23 14132.558 19.701 1.00000 131.6 15 −2800.719 15.000 1.46393 131.3 L24 16175.474 23.961 1.00000 128.5 17 −206.113 21.550 1.46393 128.8 L25 18448.714 30.024 1.00000 142.2 19 −125.627 15.558 1.61265 143.6 L26 20−1175.913 1.021 1.00000 176.8 21 −30644.154 43.644 1.46393 183.9 L31 22−162.388 1.000 1.00000 194.9 23 −485.437 28.225 1.61548 211.7 L32 24−224.099 1.000 1.00000 219.0 25 −52602.941 27.218 1.61548 230.0 L33 26−430.357 1.000 1.00000 232.6 27 590.071 26.973 1.61548 233.5 L34 28−1690.697 1.000 1.00000 232.0 29 193.801 40.140 1.61548 220.0 L35 30947.195 1.011 1.00000 211.8 31 195.275 27.215 1.46393 191.4 L36 32415.942 4.998 1.00000 179.0 33 630.902 20.876 1.61548 176.9 L41 34117.985 32.235 1.00000 142.1 35 −413.023 16.361 1.61265 140.7 L42 36225.000 31.048 1.00000 133.8 37 −142.680 15.191 1.61265 134.0 L43 38−1025.728 46.006 1.00000 146.1 39 ∞ (flat plane) 23.378 1.00000 172.1 AS40 −572.302 29.649 1.46393 185.4 L51 41 −211.448 1.002 1.00000 194.4 422551.876 32.925 1.46393 214.4 L52 43 −322.186 1.000 1.00000 219.7 44455.025 37.078 1.61548 231.9 L53 45 −625.089 10.526 1.00000 232.0 46−346.114 21.000 1.61265 231.7 L54 47 −892.299 3.534 1.00000 236.1 48340.241 42.451 1.46393 237.7 L55 49 −739.127 1.000 1.00000 235.4 50223.537 31.457 1.46393 217.7 L56 51 687.322 1.000 1.00000 210.3 52161.128 34.948 1.46393 190.4 L57 53 539.668 7.139 1.00000 179.0 542184.705 17.000 1.61265 176.9 L58 55 114.581 7.667 1.00000 143.9 56143.093 44.064 1.46393 143.3 L59 57 ∞ (flat plane) 11.847 1.00000 127.858 907.505 30.940 1.47458 114.6 L510 59 106.724 3.066 1.00000 88.8 6077.523 26.699 1.46393 85.3 L511 61 1684.716 74.2

Values Corresponding to the Conditional Expressions:

-   -   t5′=101.703    -   t5=348.210    -   f1=208.285    -   f2=−51.068    -   f3=102.936    -   f4=−69.563    -   f5=152.375    -   L=1250.000    -   φ5n=236.1    -   φ5max=237.7        φ/φexp=3.41 (L59), 2.73 (L510), 2.03 (L511)  (1)        n=1.46363 (L59), 1.47458 (L510), 1.46363 (L511)  (2)         φ/φexp=5.56 (φ: Surface No. 27 of L34)  (3)        n=1.61548  (4)        t 5 ′/t 5=0.292 (t 5′=L 59+L 510+L 511, t 5=L 51+L 52+ . . . +L        511)  (5)        f 1 /L=0.167  (6)        −f 2/L=0.041  (7)        f 3/L=0.082  (8)        −f 4/L=0.056  (9)        f 5/L=0.122  (10)        φ5n/φ5max=0.98 (φ5n: Surface No. 46 of L54, φ5max: Surface No.        48 of L55)  (11)        f/L=0.751  (12)

FIG. 3 shows the longitudinal aberration of the projection opticalsystem of the present embodiment, and FIG. 4 shows the lateralaberrations (coma aberration) occurring in the meridional (tangential)direction and the sagittal direction. In each of the aberration figures,the N.A. is the numerical aperture of the wafer W side of the projectionoptical system; and the Y is the image height of the wafer W side. Inthe astigmatic aberration figures, the dotted line indicates thetangential image plane and the solid line indicates the sagittal imageplane. Furthermore, the same reference codes are used for all thevarious aberration figures of the embodied examples that follow as inthe present embodied example. As is evident from the various aberrationfigures, the projection optical system of the present embodiment, inaddition to suppressing the reduction of the image formation performancedue to the absorption by the glass material used and favorablycorrecting in particularly the distortion in all of the broad exposureareas regardless of being both-side telecentric, it can be seen that theother aberrations are corrected in similar balance.

II. PREFERRED EMBODIMENT EXAMPLE 2

FIG. 5 is a drawing that shows the lens construction of the projectionoptical system that relates to the second embodiment. It has, in orderfrom the reticle R (object plane) as the first object, a first lensgroup G1 having a positive refractive power and with at least onenegative lens L11; and a second lens group G2 having a negativerefractive power; and a third lens group G3 having a positive refractivepower; and a fourth lens group G4 having a negative refractive power;and a fifth lens group G5 having a positive refractive power with atleast two negative lenses L54 and L58. Furthermore, it is both-sidedlytelecentric on the wafer W (image plane) side for the second object andthe reticle R (object plane) side.

Further, the lens L59, L510, L511 are comprised so as to satisfy theconditional expressions (1) and (2). In this manner, a highertransmission factor can be secured in a lens with a high energy densityof the exposure light thereby making it possible to suppress thereduction of the image formation performance that occurs due to thereduction of the transmission factor.

In addition, this embodiment preferably employs one or more lenseshaving a lens L34 that satisfies conditional expressions (3) and (4). Inthis manner, a higher refractive index can be secured in a lenscomposition with comparatively low energy density for the exposure lightthereby making favorable aberration correction possible and realizing acompact optical system.

Further, the lens L59, L510, L511 are comprised so as to satisfy theconditional expression (5). In this manner, a higher transmission factorcan be secured in a lens with a high energy density of the exposurelight thereby making it possible to suppress the reduction of the imageformation performance that occurs due to the reduction of thetransmission factor.

Moreover, the focal distance between each of the lens groups G1 throughG5 is composed so as to satisfy the conditional expressions (6) through(10). In this manner, while being both-side telecentric and securing asufficiently high numerical aperture and broad exposure area, itrealizes a high performance yet compact projection optical system whichhas the ability to very favorably correct various aberrations andespecially distortion. Furthermore, it is best when all conditionalexpressions (6) through (10) are simultaneously satisfied.

In addition, at least one negative lens L54 in the fifth lens group G5is composed so as to satisfy conditional expression (11). Accordingly,the negative spherical aberration generated by the fifth lens group G5is effectively corrected thereby making it possible to realize a highcontrast image formation on the second object W.

In Table 2, the various values of the projection optical system thatrelate to the second embodiment are illustrated.

Lens Data for Example 2

Parameters:

-   -   DO=118.644    -   WD=25.189    -   β=−0.250    -   N.A.=0.520    -   φexp=42.000    -   L=1250.000    -   F=939.108

TABLE 2 Lens Data Number R d n φ 1 941.026 22.500 1.61265 200.6 L11 2272.099 3.595 1.00000 203.6 3 284.530 40.119 1.61548 205.8 L12 4−566.773 1.000 1.00000 206.8 5 360.087 28.872 1.46393 204.7 L13 6−1929.907 1.000 1.00000 202.0 7 238.718 30.104 1.46393 192.3 L14 82940.465 1.000 1.00000 186.0 9 204.278 22.000 1.61548 171.2 L21 10120.726 17.690 1.00000 147.2 11 309.472 20.146 1.61548 146.4 L22 12137.672 20.805 1.00000 132.6 13 11217.354 18.110 1.46393 132.1 L23 14177.433 25.429 1.00000 129.2 15 −208.043 21.550 1.46393 129.8 L24 16431.365 30.552 1.00000 143.5 17 −124.350 15.425 1.61265 144.5 L25 18−1043.973 2.023 1.00000 178.4 19 −9400.162 44.515 1.46393 187.6 L31 20−163.499 1.973 1.00000 198.9 21 −504.731 29.105 1.61548 217.5 L32 22−228.074 1.000 1.00000 224.8 23 −43550.511 28.097 1.61548 236.3 L33 24−429.738 1.000 1.00000 238.9 25 523.375 28.582 1.61548 239.6 L34 26−2096.842 1.000 1.00000 237.7 27 192.750 40.981 1.61548 224.0 L35 28918.472 2.700 1.00000 215.7 29 198.092 27.472 1.46393 192.7 L36 30424.625 5.627 1.00000 179.6 31 720.205 20.495 1.61548 177.4 L41 32115.447 32.914 1.00000 141.3 33 −432.333 16.404 1.61265 139.4 L42 34225.000 26.952 1.00000 132.3 35 −147.283 17.480 1.61265 132.3 L43 36−1349.913 43.313 1.00000 144.1 37 ∞ (flat plane) 25.663 1.00000 166.6 AS38 −568.842 31.885 1.46393 181.5 L51 39 −206.204 1.000 1.00000 192.1 401210.297 32.850 1.46393 213.5 L52 41 −360.352 1.000 1.00000 218.1 42403.190 37.256 1.61548 229.0 L53 43 −694.368 10.901 1.00000 228.6 44−352.861 21.000 1.61265 228.2 L54 45 −1232.232 1.000 1.00000 231.5 46372.482 40.567 1.46393 232.5 L55 47 −619.531 1.000 1.00000 230.5 48210.349 31.297 1.46393 212.0 L56 49 610.517 1.000 1.00000 204.5 50155.645 34.480 1.46393 185.3 L57 51 516.374 7.004 1.00000 173.8 522022.223 17.000 1.61265 171.7 L58 53 111.072 7.677 1.00000 139.2 54140.438 42.404 1.46393 138.6 L59 55 ∞ (flat plane) 10.415 1.00000 123.556 1005.087 28.938 1.47458 111.9 L510 57 104.792 2.188 1.00000 87.4 5876.550 28.113 1.46393 84.5 L511 59 1934.993 72.3

Values Corresponding to the Conditional Expressions:

-   -   t5′=99.455    -   t5=345.789    -   f1=208.899    -   f2=−51.041    -   f3=103.734    -   f4=−68.649    -   f5=148.341    -   L=1250.000    -   φ5n=231.5    -   φ5max=232.5    -   F=939.165         φ/φexp=3.3 (L59), 2.66 (L510), 2.01 (L511)  (1)        n=1.46393 (L59), 1.47458 (L510), 1.46393 (L511)  (2)        φ/φexp=5.70 (φ: Surface No. 25 of L34)  (3)        n=1.61548  (4)        t 5 ′/t 5=0.288 (t 5′=L 59+L 510+L 511, t 5=L 51+L 52+ . . . +L        511)  (5)        f 1 /L=0.167  (6)        −f 2/L=0.041  (7)        f 3/i L=0.083  (8)        −f 4/L=0.055  (9)        f 5/L=0.119  (10)        φ5n/φ5max=0.98 (φ5n: Surface No. 44 of L54, φ5max: Surface No.        46 of L55)  (11)        f/L=0.751  (12)

FIGS. 6 and 7 illustrate the various aberrations of the projectionoptical system that relate to the present embodiment. As is evident fromthe figures, in addition to suppressing the reduction of the imageformation performance due to the absorption by the glass material usedand favorably correcting in particularly the distortion in all of thebroad exposure areas regardless of being both-sidedly telecentric, itcan be seen that the other aberrations are corrected in similar balancedmanner.

III. PREFERRED EMBODIMENT EXAMPLE 3

FIG. 8 shows the lens construction of the projection optical system thatrelates to a third embodiment of the present invention. It has, in orderfrom the reticle R (object plane) as the first object, a first lensgroup G1 having a positive refractive power and with at least onenegative lens L11; and a second lens group G2 having a negativerefractive power; and a third lens group G3 having a positive refractivepower; and a fourth lens group G4 having a negative refractive power;and a fifth lens group G5 having a positive refractive power with atleast two negative lenses L54 and L58. Furthermore, it is both-sidedlytelecentric on the wafer W (image plane) side for the second object andthe reticle R (object plane) side.

Further, the lens L59, L510, L511 is comprised so as to satisfy theconditional expressions (1) and (2). In this manner, a highertransmission factor can be secured in a lens with a high energy densityof the exposure light thereby making it possible to suppress thereduction of the image formation performance that occurs due to thereduction of the transmission factor.

In addition, this embodiment preferably employs one or more lenseshaving a lens L34 that satisfies conditional expressions (3) and (4). Inthis manner, a higher refractive index can be secured in a lens withcomparatively low energy density of the exposure light thereby makingfavorable aberration correction possible and realizing a compact opticalsystem.

Further, the lens L59, L510, L511 is comprised so as to satisfy theconditional expression (5). In this manner, a higher transmission factorcan be secured in a lens with a high energy density of the exposurelight thereby making it possible to suppress the reduction of the imageformation performance that occurs due to the reduction of thetransmission factor.

Moreover, the focal distance between each of the lens groups G1 throughG5 is composed so as to satisfy the conditional expressions (6) through(10). In this manner, while being both-sidedly telecentric and securinga sufficiently high numerical aperture and broad exposure area, thisembodiment realizes a high performance yet compact projection opticalsystem which has the ability to very favorably correct variousaberrations and especially distortion. Furthermore, it is best when allconditional expressions (6) through (10) are simultaneously satisfied.

In addition, at least one negative lens L54 in the fifth lens group G5is composed so as to satisfy conditional expression (11). Accordingly,the negative spherical aberration generated by the fifth lens group G5is effectively corrected thereby making it possible to realize a highcontrast image formation on the second object W.

The various values of the projection optical system that relate to thethird embodiment are provided in Table 3.

Lens Data For Example 3

Parameters:

-   -   DO=108.671    -   WD=25.136    -   β=−0.250    -   N.A.=0.520    -   φexp=42.000    -   L=1250.000    -   F=900.281

TABLE 3 Lens Data Number R d n φ 1 2014.189 18.000 1.61265 197.2 L11 2296.824 5.634 1.00000 201.4 3 317.104 37.032 1.46393 205.1 L12 4−628.560 1.000 1.00000 207.6 5 484.710 28.619 1.61548 211.5 L13 6−998.956 1.000 1.00000 210.8 7 283.130 29.908 1.61548 204.8 L14 87410.218 1.000 1.00000 199.8 9 233.039 22.251 1.61265 185.9 L21 10136.798 20.152 1.00000 163.0 11 393.096 24.589 1.61548 162.3 L22 12−774.973 1.000 1.00000 157.5 13 5200.000 15.000 1.46393 152.8 L23 14129.927 23.576 1.00000 134.4 15 −729.461 15.068 1.46393 133.9 L24 16194.388 36.002 1.00000 130.1 17 −219.245 15.371 1.46393 132.2 L25 18385.617 30.884 1.00000 141.6 19 −123.476 15.000 1.61265 142.6 L26 20−2462.517 4.749 1.00000 175.6 21 72079.272 44.358 1.46393 186.3 L31 22−164.365 1.040 1.00000 197.4 23 −430.639 26.909 1.61548 213.2 L32 24−227.560 1.000 1.00000 221.0 25 −107138.971 28.305 1.61548 233.2 L33 26−417.327 1.000 1.00000 236.1 27 318.244 36.396 1.61548 238.2 L34 28−5130.548 1.252 1.00000 235.0 29 217.233 34.322 1.61548 219.6 L35 30800.147 1.027 1.00000 211.3 31 198.579 25.327 1.46393 191.6 L36 32365.795 5.187 1.00000 178.9 33 495.017 16.558 1.61548 176.2 L41 34123.560 31.738 1.00000 145.7 35 −408.905 15.466 1.61265 144.7 L42 36223.379 29.466 1.00000 136.7 37 −144.209 15.023 1.61265 136.7 L43 38−1282.715 45.782 1.00000 148.4 39 ∞ (flat plane) 23.833 1.00000 172.9 AS40 −648.777 28.616 1.46393 186.8 L51 41 −213.845 1.095 1.00000 194.5 421004.569 37.827 1.46393 215.1 L52 43 −306.465 2.196 1.00000 219.7 44546.948 30.975 1.61548 227.6 L53 45 −836.559 13.854 1.00000 227.3 46−331.552 18.523 1.61265 227.0 L54 47 −640.300 1.000 1.00000 231.1 48253.111 41.066 1.46393 231.7 L55 49 −3935.806 1.000 1.00000 228.2 50231.463 26.916 1.46393 214.2 L56 51 463.993 12.973 1.00000 206.1 52157.799 34.930 1.46393 183.1 L57 53 616.457 5.379 1.00000 172.0 541269.284 15.127 1.61265 169.1 L58 55 100.172 13.803 1.00000 137.3 56104.074 37.360 1.46393 134.4 L59 57 ∞ (flat plane) 16.576 1.00000 125.958 704.105 15.290 1.46393 106.5 L510 59 129.344 5.677 1.00000 90.8 6085.802 26.186 1.46393 84.6 L511 61 359.698 70.5

Values Corresponding to the Conditional Expressions:

-   -   t5′=78.835    -   t5=312.789    -   f1=226.531    -   f2=−53.700    -   f3=104.222    -   f4=−72.830    -   f5=153.351    -   L=1250.000    -   φ5n=231.1    -   φ5max=231.7    -   F=939.165        φ/φexp=3.2 (L59), 2.54 (L510), 2.01 (L511)  (1)        n=1.46393 (L59), 1.46393 (L510), 1.46393 (L511)  (2)        φ/φexp=5.67 (φ: Surface No. 27 of L34)  (3)        n=1.61548  (4)         t 5 ′/t 5=0.252 (t 5 ′=L 59+L 510+L 511, t 5 =L 51+L 52+ . . .        +L 511)  (5)        f 1 /L=0.181  (6)        −f 2/L=0.043  (7)        f 3/L=0.083  (8)        −f 4/L=0.058  (9)        f 5/L=0.123  (10)        φ5n/φ5max=0.98 (φ5n: Surface No. 46 of L54, (φ5max: Surface No.        48 of L55)  (11)        f/L=0.751  (12)

FIGS. 9 and 10 are drawings showing the various aberrations of thepresent embodiment. As is evident from the figures, the projectionoptical system of the present embodiment, in addition to suppressing thereduction of the image formation performance due to the absorption bythe glass material used and favorably correcting in particularly thedistortion in all of the broad exposure areas regardless of beingboth-sided telecentric, it can be seen that the other aberrations arecorrected in similar balance.

Moreover, in each of the above embodied examples, although an ultra-highpressure mercury vapor lamp that supplies a light that includes an iline (λ=365 nm) was applied as the light source, a discharge lampsupplying light that includes a g line (λ=436 nm) and an h line (λ=404nm), and a laser beam that supplies light of a deep ultraviolet(far-ultraviolet) region and a vacuum ultraviolet region can also beapplied as the light source L. When using a laser light source as thelight source, a beam attenuator for control an exposure dose and a beamshaping optical system for forming a predetermined size and shape of thebeam cross-section of the laser beam from the light source L, are to bearranged in the illumination system. Further, when the light source L isarranged separately from the projection exposure apparatus body, it isbest to arrange an automatic beam steering unit which always faces thedirection of the light from the light source L towards the projectionexposure apparatus body side.

When using a light source that supplies an exposure light of a DUV (DeepUltraViolet) region and a VUV (Vacuum UltraViolet) region, it is best ifthe optical path between the light source L and the illumination systemIS is sealed with a casing, and the air space from the light source L tothe optical member parts of the extreme reticle side of the illuminationsystem IS is replaced with an inert gas such as noble (rare) gas (e.g.,helium gas, nitrogen gas) being a gas with a low absorption ratio forexposure light. At this time, the interior of the projection opticalsystem PL is comprised so as to be maintain a sealed condition betweenthe optical member parts that are arranged to the extreme wafer side andthe optical member parts that are arranged on the extreme reticle sidefrom among the optical member parts comprising the projection opticalsystem; and it is best when the gas on the inside of the projectionoptical system PL is replaced with an inert gas such as noble (rare) gas(e.g., helium, nitrogen gas).

Furthermore, with the form of the embodiment described above, the caseis described where the rectangular shaped area (for example 26 mm×33 mm)inscribed within the circle having a diameter of φmax undergoes exposureat once as the exposure area, and the rectangular shaped area inscribedwithin the circle has the shape of a slit or a slot wherebyscan-exposure can be performed when starting the movement of the reticleR and the wafer W. In this case, the exposure light is supplied againstthe rectangular shaped (slit shaped) area (illumination area) having ashort border along the X direction and a long border along the Ydirection from among all the pattern areas on the reticle R, and bycausing the reticle stage RS and the wafer stage WS, or the reticle Rand the wafer W, to move (scan) synchronously in the X directionaccording to the speed ratio that corresponds to the magnification ofthe projection optical system PL, the mask pattern is swept andundergoes exposure against the area (shot area) having the length thatcorresponds to the scan amount (movement amount) of the wafer W as wellas having a width that is equal to the long border of the exposure areaon wafer W.

In addition, with each embodiment described above, the lens surfaces ofeach lens in the projection optical system PL are all sphericallyshaped, however, one or more lens surfaces may have an aspherical(non-spherical) shape in order to achieve at least one objective byfurther increasing the exposure area of the projection optical system PLand further increasing the numerical aperture of the projection opticalsystem PL.

IV. PREFERRED EMBODIMENT EXAMPLE 4

FIG. 11 is a flow chart of the semiconductor device manufacturing methodcomprising a predetermined circuit pattern on a wafer by using theexposure apparatus that provides the projection optical system of eachof the embodiments described above.

In Step 1, a metal film is vapor deposited on one lot of wafers. In thesubsequent Step 2, a photoresist is applied to the metal film on the onelot of wafers. Thereafter, in Step 3, the image of the pattern on thereticle R is sequentially exposed and transferred, through theprojection optical system thereof, to each shot area on the one lot ofwafers by using the projection exposure apparatus of FIG. 1 thatprovides the projection optical system of the embodiment describedabove. Thereafter, in Step 4, after the developing of the photoresist onthe one lot of wafers, in Step 5, by etching the resist pattern on theone lot of wafers as a mask, the circuit pattern that corresponds to thepattern on the reticle R is formed in each shot area on each wafer.Thereafter, by forming the circuit pattern on a further layer, thedevice of the semiconductor element is manufactured.

As described above, the projection optical system of each of theembodiments, while being both-sidedly telecentric, and in addition tosuppressing the reduction of the image formation performance that occursdue to the absorption by the glass material used, and on account ofincreasing the numerical aperture N.A., and even when there is a bend inthe reticle R and a bend on each wafer of the exposure subject, arefined circuit pattern can be formed with stability and with a highresolution on each wafer. Furthermore, since the exposure area of theprojection optical system is broad, a large device with a highthroughput can be manufactured.

Further, the present invention can be applied to both the Step andRepeat method (batch exposure method) which, after transferring at oncethe mask pattern image to one shot area on the wafer repeats the processwhere the wafers within the plane that is orthogonal to the optical axisof the projection optical system are consecutively and two dimensionallymoved, then the mask pattern image is transferred in one batch to thenext shot area, and the Step and Scan method (scan-exposure method)which performs synchronous scanning of the mask and wafer, with aprojection magnification b against the projection optical system as aspeed ratio, at the time of exposure to each shot area of the wafer.Moreover, since the Step and Scan method is best provided the favorableimage formation performance can be attained within the exposure area ofthe slit shape (thin, long shape), exposure to a broader shot area onthe wafer becomes possible without enlarging the projection opticalsystem.

V. PREFERRED EMBODIMENT EXAMPLE 5

In the photolithography process for manufacturing a semiconductorelement device or so forth, a reduction projection exposure apparatus(stepper, scanner, or so forth) is used. In general, a semiconductorelement device such as an ultra LSI is formed by over-laying multiplelayers on to a wafer, however, of those layers, the layer requiring thehighest resolution is called the critical layer. In contrast to this,the layers that do not require a high resolution, such as the ionimplant layers that are used when manufacturing, for example,semiconductor memory, are called the middle layers. For example, inrecent manufacturing factories of ultra LSI, it is becoming more commonto distinguish between different exposure devices when performingexposure between different layers within the manufacturing process of asingle type of ultra LSI. Therefore, when manufacturing ultra LSI havingboth a critical layer and a middle layer, it is common to performexposure using a so-called Mix-and-Match method where the exposure ofthe critical layer is performed with a projection exposure apparatushaving a high resolution, and the exposure of the middle layer isperformed by a projection exposure apparatus of a relatively rougherresolution.

Hereafter, an explanation will be provided of the exposure method thatuses the scanning type projection exposure apparatus (the projectionexposure apparatus of the Step and Scan method) which has a highresolution to the exposure of the critical layer, and the exposuremethod that uses the batch exposure type projection exposure apparatus(stepper) for exposure to the middle layer.

FIG. 12 shows the exposure system of the present example. In thisfigure, the projection exposure apparatus of the Step and Scan method(hereinafter referred to as a “scanner”) 1A is arranged, and theprojection exposure apparatus of the batch exposure method (hereinafterreferred to as a “Stepper”) 1B is arranged. In the present example, theScanner 1A has a high resolution and the Stepper 1B has a lowresolution. Using the scanner 1A, exposure of the critical layer isperformed on the wafer; and using the stepper 1B, exposure of the middlelayer is performed on the wafer.

First, in the scanner of FIG. 12, the portion 13A of pattern area 3A ofthe reticle RA is illuminated by the exposure light from theillumination system 2A, and a portion of the pattern image thereof isreduced to ¼ size through the projection optical system 4A whereby it isprojection exposed to the slit shaped exposure area 14 on the wafer Wthat is held on top of the wafer stage 5A. Here, in the same manner asin FIG. 1, the Z axis is placed parallel to the optical axis of theprojection optical system 3A thereby making the X axis and the Y axis tobe on intercepting coordinates on a flat plane orthogonal to the Z axis.In this state, by having the reticle RA scan in the −Y direction (or the+Y direction) while simultaneously having the wafer W scan in the +Ydirection (or the −Y direction), the pattern image within the patternarea 2A of the reticle RA will be consecutively projected to theexposure field 6A on the wafer W.

The position of the reticle stage not shown in the figure that scans thereticle RA of the scanning type exposure device 1A is measured by alaser interferometer not shown in the figure, and the X coordinates ofthe wafer stage 5A is measured by the moving mirror 7A and the laserinterferometer 8A, and the Y coordinates of the wafer stage 5A ismeasured by the moving mirror 9A and the laser interferometer 10A, andeach of the measured coordinates are supplied to a control device notshown in the figure. This control device also controls the synchronizedmovement of the reticle stage not shown in the figure and the waferstage 5A.

Moreover, as such a scanner, the devices disclosed in, for example, U.S.Pat. Nos. 5,194,893, and 5,473,410, and 5,477,304 can be used. Thepresent invention incorporates by reference the teaching of each ofthese patents.

Next, with the Stepper 1B, the pattern area 3B on the reticle RB isilluminated by the exposure light from the illumination system 2B, andthe pattern in the pattern area 3B is reduced to ¼ size by theprojection optical system 4B whereby it is projection exposed to therectangular exposure field 6B of the wafer W. The wafer W is secured tothe wafer stage 5B, and the wafer stage 5B is constructed from the Zstage that establishes the exposure plane of the wafer W in the Z axisdirection into the best focus position, and from the XY stages thatdetermine the position of the wafer W in the direction of the X axis andthe Y axis. There are two movement mirrors 7B and 9B fixed to the waferstage 5B so as to be orthogonal, and the coordinates of the X directionof the wafer stage 6B are measured by the movement mirror 7B and thelaser interferometer 8B being attached on the exterior, while thecoordinates of the Y direction of the wafer stage 6B are measured by themovement mirror 9B and the laser interferometer 10B being attached onthe exterior. The coordinates that are measured by the laserinterferometers 8B and 10B are supplied to the control device not shownin the figure that controls the movement of the entire device, and thiscontrol device, performs the position determination of the wafer W bythe stepping drive of the wafer stage 6B through the drive component notshown in the figure, in the X direction and the Z direction.

Now, as shown in FIG. 13A, the projection optical system 4A of thescanner 1A of the present example has a circular image field 20A with adiameter of φ_(20A). Furthermore, the slit shaped exposure area 14 is ofa size of 25 mm×8 mm, and it is nearly inscribed within the circularimage field 20A. Since this slit shaped exposure area 14 is scanned(swept) along the direction of the X axis in the figure over the waferW, it becomes possible for the exposure field 6A of 25 mm×33 mm to beformed over the wafer W. Moreover, in the present example, φ_(20A)=26.4mm.

Furthermore, as shown in FIG. 13B, the projection optical system 4B ofthe stepper 1B of the present example has a circular image field 20Bwith a diameter of φ_(20B) (the φexp in the embodiment described above).Furthermore, the exposure field 6B that is formed at the time of thebatch exposure over the wafer W is a size of 25 mm×33 mm. Moreover, inthe present example, φ_(20B)=42 mm.

The construction of the stepper 1B of the present example will beexplained with reference to FIG. 14. The light source L from the ultrahigh pressure mercury vapor lamp that supplies a light that includes anemission light of an i line for example, is arranged in the one focalpoint of the ellipse mirror 11, and the light from the light source L,after passing through the folding mirror FL1, gathers in the other focalpoint of the ellipse mirror 11 thereby forming a light source image. Inthe vicinity of this light source image, the shutter 13 is arranged forturning ON and OFF the exposure light. The light that passes through theshutter 13 is converted into a nearly parallel beam through the inputlens 14 whose position is determined by the first (frontwise) focalpoint positioned in the vicinity of the light source image. A comaticprism 15 having a concave cone shape at the entry plane and a convexcone shape at the exit plane, is arranged to be in the optical path ofthe beam from the input lens 14, and the light that travels via thiscomatic prism 15 is converted into an annular shaped (a doughnut shaped)beam where the cross-section has a light intensity distribution of anannular (doughnut) shape.

This type of comatic prism is disclosed in, for example, U.S. Pat. No.4,498,742. Moreover, with the comatic prism disclosed in this patent,the entry side and the exit side are used in opposite directions. Thepresent invention incorporates by reference the teaching of U.S. Pat.No. 4,498,742 described above.

The annular shaped beam from the comatic prism 15 enters the fly's eyelens FE that is formed by integrating a plurality of bar shaped lenselements into a two dimensional matrix. The aggregate, or in otherwords, the planar light source (secondary light source) of the lightsource image that is collected by each of the bar-shaped lens elementsis formed in the vicinity of the exit plane of the fly's eye lens FE.Here, since the light intensity distribution of the cross-section of theentry beam into the fly's eye lens FE is nearly annular shaped, theshape of the secondary light source also becomes annular shaped.

In the present example, the illumination aperture stop S (σ(sigma) stopS) having a circular shaped opening is arranged to the planer lightsource forming position. Moreover, this planer light source formingposition is conjugate with the pupil position of the projection opticalsystem 4B (PL) to be described hereafter, and it is called theillumination pupil of the illumination system. Moreover, the shape ofthe opening of the illumination stop shape S is best if it is an annularshape.

In this manner, in the present example, the light intensity distributionof the secondary light source occurring in the illumination pupil is setso that the light intensity at the pupil center area including theoptical axis is smaller than the peripheral area of said pupil centerarea.

The light from the illumination aperture stop S is collected by thecondenser lens system 17 a and 17 b being positioned by the first(frontwise) focal point in the planer light source forming position, andit illuminates in superposing manner the illumination field stop 18heavily the illumination field of view diaphragm 18 having a rectangularshaped opening that is similar to the shape of the pattern area 3B overthe reticle RB.

The beam that passed through the illumination field stop 18 passesthrough the illumination field stop image forming optical system 19 athrough 19 c that works optically conjugate with the illumination fieldstop 18 and the pattern plane of the reticle RB (wafer W plane), as wellas the folding mirror FL2 that is arranged at the illumination fieldstop image forming optical system thereby reaching the reticle RB. Atthis time, the illumination area that is the image of the opening of theillumination field stop 18 is formed on the reticle RB.

The reticle RB, in the same manner as shown in FIG. 1, is held by way ofthe reticle holder RH, and this reticle holder RH is secured parallel tothe XY plane on the reticle stage RS. The reticle stage RS in the FIG.14 is constructed so as to be movable in XY direction and to berotatable about rotating direction (θz direction) with the Z axis as thecenter, and these rotation position coordinates are measured by theinterferometer 12B using the moving mirror 11B including a corner cubeor so forth. Further, the rotation position control of the reticle RB isdone by way of the drive component not shown in the figure.

The light from the pattern formed by the reticle RB, through theprojection optical system 4B (PL), forms the reduced image of thepattern in the pattern area 3B on the reticle RB within the exposurefield on the wafer W that is applied by the photosensitive material.Moreover, the projection optical system of any of the embodied examples1 through 3 described above can be applied as the projection opticalsystem 4B (PL). An aperture stop as with a variable aperture diameter isarranged in the vicinity of the pupil position of this projectionoptical system 4B (PL).

The wafer W, similar to the example shown in FIG. 1, is held by thewafer holder WH, and the wafer holder WH is attached to the wafer stageWS with the ability to move within the XY plane.

In this manner, as in the example of FIG. 14, the pattern on the reticlecan be projection exposed onto the wafer by using the annularillumination. Moreover, this type of projection exposure apparatus isdisclosed in, for example, U.S. Pat. No. 5,530,518, and the teachings ofU.S. Pat. No. 5,530,518 are hereby incorporated by reference.

Now, with the projection exposure apparatus of the present example,since the light intensity distribution of the secondary light sourceoccurring in the illumination pupil is set so that the light intensityat the pupil central area including the optical axis is smaller than theperipheral area of said pupil central area, and since it is possible tominimize the irradiation expansion of the optical elements in theprojection optical system, it becomes possible to maintain a high imageformation performance.

Furthermore, in the case when the distribution of the secondary lightsource occurring in the illumination pupil is annularly shaped, it isbest when the annular ratio of inner diameter to outer diameter of theannular shaped light intensity distribution is set to be within therange of 0.3 through 0.7. Here, when the lower limit value of the rangedescribed above is exceeded, the inner diameter of the annular shapedsecondary light source becomes too small, and it becomes difficult toimprove depth of focus as well as resolution of the projection opticalsystem. On the other hand, when the exceeding the upper limit value ofthe range described above, the width of each line forming a pattern orpatterns on a reticle, which width is uniform and the same, becomesuneven or varied depending on repetition of the lines or line-to-linedistances of the pattern when transferred onto the wafer. Accordingly,it is not possible to transfer the pattern on the reticle onto the waferaccurately. Further, since the degree of variance of the line width tothe exposure variance amount becomes greater, it becomes difficult toform a pattern of a desired line width on the wafer.

With the present example, with the ratio of the inner diameter to theouter diameter of the annular shaped light intensity distribution, theso-called annular ratio becomes set at nearly ⅓, and by using theprojection optical system that relates to either of the embodiedexamples 1 through 3 described above, it becomes possible to achieve aresolving power (resolution) of 0.35 nm in the image field diameter of42 mm on the wafer. Accordingly, with the stepper 1B of the presentexample, it is possible to perform batch exposure under a resolvingpower of 0.35 nm with respect to the exposure field of 25 mm×33 mm thatis inscribed in the image field of a diameter of 42 mm.

Moreover, with the projection exposure apparatus of the present example,by using the comatic prism 15, and since annular illumination can beperformed essentially without loss of light quantity, there is littlerisk of bringing about the reduction of the throughput.

In the example shown in the FIG. 14, the fly's eye lens FE is used asthe optical integrator. However, a Rod type integrator (a internalreflection type integrator, a light pipe, a light tunnel, a glass rod,etc.) can be used as the optical integrator. The combination of the rodtype integrator and the annular illumination is described in, forexample, U.S. Pat. Nos. 5,359,388; 5,330,518; 5,675,401; 5,648,715. Thepresent invention incorporates by reference the teachings of each ofthese patents.

Next, a description of one example of the exposure action or processoccurring in the exposure system indicated in FIG. 12 will be given withreference to FIG. 15. In the following description, an example of theexposure of the middle layer after the exposure of the critical layerwill be given.

In Step 11, a metal film is arranged on one lot of wafers. In the nextStep 12, the photoresist is applied as a photosensitive material ontothe metal film on the one lot of wafers.

Thereafter, in Step 13, the wafer W is positioned on the wafer stage 5Aof the scanner 1A of FIG. 12, and the reduced image of the pattern ofthe reticle RA is exposed with the sequential Step and Scan method tothe multiple shot areas that are arranged with the exposure field 6A asthe unit on the wafer W.

Thereafter, the photoresist is developed on the exposed one lot ofwafers in Step 14, and in Step 15, the one lot of wafers is etched usingthe developed resist pattern as a mask. In this manner, the processingof the critical layer is completed.

Next, in Step 16, a metal film is attached onto the one lot of wafersdescribed above. In the next step 17, the photoresist is applied as aphotosensitive material on the metal film on the one lot of wafersthereof.

Furthermore, in Step 18, this wafer is positioned on the wafer stage 5Bof the Stepper 1B of FIG. 12, and the batch exposure of the reducedimage of the pattern of the reticle RA is repeated by the sequentialStep and Repeat method to the multiple shot areas being arranged withthe exposure field 6B as the unit on the wafer W.

Thereafter, in Step 19, the photoresist is developed on the exposed onelot of wafers, and in Step 20, the one lot of wafers is etched using thedeveloped resist pattern as a mask. In this manner, the processing ofthe middle layer is completed.

In actuality, the exposure of the critical layer and the exposure of themiddle layer is repeated until the circuit pattern of the top layer isformed and as a result, the semiconductor device is manufactured.

Furthermore, in the example described above, the exposure of the middlelayer was performed after the exposure of the critical layer, however,the case may exist where the opposite occurs, in other words, theexposure of the critical layer is performed after the exposure of themiddle layer. In such a case, with the description given above, theexposure occurring by way of the Scanner 1A and the exposure by way ofthe Stepper 1B can be interchanged.

In the example described above, since the Stepper 1B has the sameexposure field size as maximum exposure field size (e.g., 25×33 mm,26×33 mm) of the Scanner 1A, it is possible to obtain maximum throughputon the Scanner, to obtain tight overlay control, and to simplifymatching strategy. Since the Stepper 1B has same projectionmagnification as the Scanner 1B thereof, it is possible to securereticle compatibility.

On the other hand, in the case where the Stepper 1B has a smallerexposure field size (e.g., 22×22 mm) than the maximum exposure fieldsize of the Scanner 1A, the exposure field size of the Scanner 1A mustbe greatly limited in order to obtain concentric matching and avoiddecreasing throughput. In the case where the Stepper 1B has a smallerexposure field size than the maximum exposure field size of the Scanner1A, the exposure field size of the Scanner 1A does not need to belimited in order to establish non-concentric matching (e.g., 2 in 1 or 3in 1 non-concentric matching (two or three stepper fields within onescanner field)). However, the distortion fingerprint in the exposurefield of the Scanner 1A needs to overlay the distortion fingerprints intwo or three exposure fields of the Stepper 1B, thereby bringing aboutdifficulty in overlay control.

In the case where the projection magnification of the Stepper 1B differsfrom the Scanner thereof, reticle incompatibility is brought about.

Furthermore, in the example described above, the same projectionmagnification ratio was used for the Stepper 1B for the middle layerexposure and the Scanner 1A for the critical layer exposure, but theseprojection magnification ratios can also be different when reticlecompatibility is not required.

Further, in the example described above, the same size (25 mm×33 mm) wasestablished for the exposure field 6A of the Scanner 1A for the criticallayer exposure and the exposure field 6B of the Stepper 1B for themiddle layer exposure. However, as long as the exposure field 6B of theStepper for the middle layer exposure is of a size that can encompassthe exposure field 6A of the scanning type exposure device 1A, it isacceptable when simple matching strategy and tight overlay controllerreticle compatibility are not required. Furthermore, the exposure field6B of the Stepper 1B for the middle layer exposure is not limited to asize of 25 mm×33 mm. It may also be an exposure field that encompassesan area of 25 mm×33 mm such as, for example, 26 mm×33 mm.

Moreover, in the example described above, the slit shaped exposure areaof the Scanner 1A for the critical layer exposure is not limited to 25mm×8 mm. It may be a size of, for example, 25 mm×6 mm or 26 mm×6 mm.

With each of the Embodiments described above, the present invention canbe applied to a projection exposure apparatus that is used in themanufacture of a semiconductor element device. Moreover, the presentinvention is not limited to only a projection exposure apparatus used inthe manufacture of a semiconductor element device. Instead, the presentinvention can be applied to an exposure apparatus that transfers adevice pattern onto a glass or a plastic plate and which is used in themanufacture of a flat panel display such as a LCD (liquid crystaldisplay), a PDP (plasma display panel), EL (electroluminescent) display,FED (field emission display), Electric Paper display, etc., or anexposure apparatus that transfers a device pattern onto a ceramic waferand which is used in the manufacture of a thin film magnetic head, or anexposure apparatus that is used in the manufacture of an image pickupdevice such as a CCD (charged-coupled device) and so forth. Furthermore,the present invention can also be applied to an exposure apparatus thattransfers a circuit pattern to a silicon wafer or a glass substrate inorder to manufacture a reticle or a mask.

Additionally, the present invention is not limited to the forms of theembodiments described above. Indeed, the present invention encompassesvarious combinations of compositions that do not exceed the bounds ofthe essence of the present invention.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only. Thus, it should be understoodthat the invention is not limited to the illustrative examples in thisspecification. Rather, the invention is intended to cover allmodifications and variations that come within the scope of the followingclaims and their equivalents.

1. A projection optical system for projecting onto a workpiece a reduced image pattern arranged on a mask based on the exposure light of a predetermined wavelength, comprising: a plurality of optical elements arranged to each receive the exposure light, each of the plurality of optical elements being shaped and positioned such that both sides of the mask and the workpiece are set to be telecentric; wherein the plurality of optical elements comprises: a first lens group arranged between a first object and a second object; a second lens group having a negative power, and arranged between the first lens group and the second object; a third lens group having a positive power and arranged between the second lens group and the second object; a fourth lens group having a negative power and arranged between the third lens group and the second object; a fifth lens group having a positive power and arranged between the fourth lens group and the second object; wherein two lens surfaces of the first lens group satisfy the condition φ₁/φ_(exp)≦3.5, the first material satisfies the condition n₁≦1.57, the projection optical system including a second lens made of a second material, two lens surfaces of the second lens satisfy the condition φ₁/φ_(exp)>3.5, and the second material satisfies the condition n₂>1.57, where φ_(exp) is designated as a diameter of an exposure area on the second object, φ₁ is designated as a diameter of a clear aperture of the two lens surfaces of the first lens group, φ₂ is designated as a diameter of a clear aperture of the two lens surfaces of the second lens, and n₁ is designated as a refractive index of the first lens, and n₂ represents a refractive index of the second lens; and wherein the projection optical system includes an image circle having a diameter of at least 42 mm and a maximum value of a numerical aperture at a side of the workpiece is determined to be greater than or equal to 0.5.
 2. The projection optical system of claim 1, wherein each of the plurality of optical elements is arranged along an optical axis that extends along a straight line.
 3. The projection optical system of claim 1, wherein a sum of axial thickness of a first lens in the fifth lens group divided by a sum of axial thickness of all lenses in the fifth lens group is greater than or equal to 0.2.
 4. The projection optical system of claim 3, wherein at least one conditional expression is satisfied among the following conditional expressions: 0.04<f ₁ /L<0.4 0.015<f ₂ /L<0.15 0.02<f ₃ /L<0.2 0.015<f ₄ /L<0.15 0.03<f ₅ /L<0.3, where the focal length of the first lens group is designated as f₁, the focal length of the second lens group is designated as f₂, the focal length of the third lens group is designated as f₃, the focal length of the fourth lens group is designated as f₄, the focal length of the fifth lens group is designated as f₅, and L is designated as the axial distance between the first object and the second object.
 5. The projection optical system of claim 4, wherein a maximum clear aperture among clear apertures of negatives lenses in the fifth lens group divided by a maximum clear aperture among clear apertures of a plurality of lenses in the fifth lens group is greater than or equal to 0.7.
 6. The projection optical system of claim 5, wherein the focal length of the projection optical system divided by the distance between the first object and the second object is greater than or equal to 0.6.
 7. The projection optical system of claim 1, wherein at least one conditional expression is satisfied among the following conditional expressions: 0.04<f ₁ /L<0.4 0.015<f ₂ /L<0.15 0.02<f ₃/L<0.2 0.015<f ₄ /L<0.15 0.03<f ₅ /L<0.3, where the focal length of the first lens group is designated as f₁, the focal length of the second lens group is designated as f₂, the focal length of the third lens group is designated as f₃, the focal length of the fourth lens group is designated as f₄, the focal length of the fifth lens group is designated as f₅, and L is designated as the axial distance between the first object and the second object.
 8. The projection optical system of claim 7, wherein each the following conditional expressions are satisfied simultaneously: 0.04<f ₁ /L<0.4 0.015<f ₂ /L<0.15 0.02<f ₃ /L<0.2 0.015f ₄ /L<0.15 0.03<f ₅ /L<0.3.
 9. The projection optical system of claim 8, wherein a maximum clear aperture among clear apertures of negatives lenses in the fifth lens group divided by a maximum clear aperture among the clear apertures of a plurality of lenses in the fifth lens group is greater than or equal to 0.7.
 10. The projection optical system of claim 9, wherein the focal length of the projection optical system divided by the distance between the first object and the second object is greater than or equal to 0.6.
 11. The projection optical system of claim 1, wherein a maximum clear aperture among clear apertures of negatives lenses in the fifth lens group divided by a maximum clear aperture among the clear apertures of a plurality of lenses in the fifth lens group is greater than or equal to 0.7.
 12. The projection optical system of claim 11, wherein each of the following conditional expressions are satisfied simultaneously: 0.04<f ₁ /L<0.4 0.015<f ₂ /L<0.15 0.02<f ₃ /L<0.2 0.015f ₄ /L<0.15 0.03<f ₅ /L<0.3.
 13. The projection optical system of claim 12, wherein the focal length of the projection optical system divided by the distance between the first object and the second object is greater than or equal to 0.6.
 14. The projection optical system of claim 1, wherein the focal length of the projection optical system divided by a distance between the first object and the second object is greater than or equal to 0.6.
 15. The projection optical system of claim 14, wherein each of the following conditional expressions are satisfied simultaneously: 0.04<f ₁ /L<0.4 0.015<f ₂ /L<0.15 0.02<f ₃ /L<0.2 0.015<f ₄ /L<0.15 0.03f ₅ /L<0.3.
 16. A projection exposure apparatus for projecting an image of patterns formed on a mask onto a workpiece, comprising: a first stage that secures a mask as a first object; an illumination system that illuminates an exposure light of a predetermined wavelength; a second stage that secures the workpiece as a second object; and a projection optical system of claim 1, which is arranged in an optical path between the mask and the workpiece.
 17. A method for transferring a pattern arranged on a mask onto a workpiece, comprising the steps of: providing a projection optical system of claim 1; illuminating the mask by use of a predetermined wavelength; and operating the projection optical system so as to form in one lot a reduced image of an illuminated the mask into a predetermined field on the workpiece.
 18. The projection optical system of claim 1, wherein the first lens group has a positive power. 